Hey there!
Molar mass Na2SO4 = 142.04 g/mol
Number of moles:
n = m / mm
n = 25 / 142.04
n = 0.176 moles of Na2SO4
Therefore, use the Avogadro constant
1 mole Na2SO4 ------------------- 6.02x10²³ molecules
0.176 moles Na2SO4 ------------ molecules ??
0.176 x ( 6.02x10²³ ) / 1
=> 1.059x10²³ molecules of Na2SO4
hope this helps!
The time take for the train to travel 950 Km is 7.92 h
<h3>What is speed? </h3>
Speed is the distance travelled per unit. Mathematically, it can be expressed as:
Speed = distance / time
With the above formula, we can determine the time. Details below:
<h3>How to determine the time</h3>
The time taken for the train t travel 950 Km can be obtained as follow:
- Speed = 120 Km/h
- Distance = 950 Km
- Time =?
Speed = distance / time
120= 950 / time
Cross multiply
120 × time = 950
Divide both side by 120
Time = 950 / 120
Time = 7.92 h
Learn more about speed:
brainly.com/question/680492
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Answer:
14 g of N2
Explanation:
If we look at the options, we will notice that the correct answer needs to be a gas that has about half of the molecular mass of the gas.
If we consider nitrogen gas whose molecular mass is 28g/mol, half of the molecular mass is 14 g.
So;
28g of N2 contains 6.02 × 10^23 molecules of N2
14g of N2 contains 14 × 6.02 × 10^23 /28
= 3.0 x 10^23
Answer:
The specific heat capacity of silver is 0.24 j/g.°C.
Explanation:
Given data:
Mass of sample = 55.00 g
increase of temperature ΔT= 15.0 °C
Heat absorbed = 193.9 J
Specific heat capacity of silver = ?
Solution:
Specific heat capacity:
It is the amount of heat required to raise the temperature of one gram of substance by one degree.
Formula:
Q = m.c. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance.
ΔT = change in temperature
Now we will put the values in formula.
193.9 J = 55.00 g × c ×15.0 °C
193.9 J = 825 g.°C × c
c = 193.9 J / 825 g.°C
c= 0.24 /g.°C
The specific heat capacity of silver is 0.24 j/g.°C.
